LevelDb backed DB now works
Merge branch 'leveldb' into develop

Implements a LevelDb backed store as the only persisted storage system; the FileDb based one
was just not up to snuff for anything that needed to be stable.

More work needs to be done on LevelDb to make it faster and more stable, such as
allowing for improperly sized image data retrieved to be ignored instead of failing
on it, as well as storing bucket sizes in the DB (under some sort of unique key)
to speed up loading and lower overhead for a freshly loaded DB.

Querying needs to be made multithreaded; that'd be super easy, and a set of standalone
binaries for directly modifying a database should be created to ease automated DB
maintenance.
Merge branch 'develop'